Hirudinella ventricosa (Pallas, 1774) Baird, 1853 represents a species complex based on ribosomal DNA

Abstract

Digeneans in the genus Hirudinella de Blainville, 1828 (Hirudinellidae) from three species of pelagic fishes, Acanthocybium solandri (Cuvier), Makaira nigricans Lacépède and Thunnus albacares (Bonnaterre), and one benthic fish, Mulloidichthys martinicus (Cuvier), from the Gulf of Mexico are investigated using comparison of ribosomal DNA. Four species are identified based on molecular differences: Hirudinella ventricosa (Pallas, 1774) Baird, 1853 from A. solandri, Hirudinella ahi Yamaguti, 1970 from T. albacares, and two unidentified but distinct species of Hirudinella, herein referred to as Hirudinella sp. A (from both M. nigricans and M. martinicus) and Hirudinella sp. B from M. nigricans. Additionally, H. ahi, based tentatively on morphological identification, is reported from Thunnus thynnus (Linnaeus). This represents the first record of a hirudinellid from M. martinicus and the first record of H. ahi from T. thynnus. A phylogeny of some Hemiurata Skrjabin & Guschanskaja, 1954 using partial fragments of the 28S rDNA sequences is consistent with earlier phylogenies and the position of the Hirudinellidae Dollfus, 1932 is well-supported as a derived group most closely related to the Syncoeliidae Looss, 1899.

Proterometra epholkos sp. n. (Digenea: Azygiidae) from Terrapin Creek, Alabama, USA: Molecular characterization of life cycle, redescription of Proterometra albacauda, and updated lists of host and geographic locality records for Proterometra spp. in North America

“…Before the present study, GenBank held sequence data for 3 markers ( [43]. As additional studies incorporate and publish azygiid molecular sequence data, a better understanding of interrelationships of azygiid genera will likely emerge; however, at present, impactful phylogenetics is out of reach, simply for lack of available sequence data.…”

“…Including the present study, molecular sequence data exist only for Proterometra sp. [43] and P. epholkos, despite marked advances in molecular systematics of trematodes [76]. Sequence data for the commonly applied markers (ITS2, 18S, 28S) can help throw light on the identity of species that have been reported in the literature.…”

“…Another gap comprises the fact that molecular data have yet to be employed in differentiating species of Proterometra; one sequence (28S) exists in GenBank (Proterometra sp.) [43].…”

A species pair of Bivesicula Yamaguti, 1934 (Trematoda: Bivesiculidae) in unrelated Great Barrier Reef fishes: implications for the basis of speciation in coral reef fish trematodes

“…Jousson et al, 2000;Hunter et al, 2010;Calhoun et al, 2013;Curran et al, 2013). Especially where the species occur in sympatry, we suspect that circumstances comparable to those discussed above have underpinned trematode speciation.…”

A review on the molecular characterization of digenean parasites using molecular markers with special reference to ITS region

“…Calhoun et al (2013) identifi ed four species of Hirudinella (H. ventricosa, H. ahi and two unidentifi ed species) from Gulf of Mexico on the basis of 3' end of 18S, ITS-1, 5.8S, ITS-2 and 5' end of 28S (D1-D3 domain) region sequences. Through analyses of especially ITS region, it was observed that Hirudinella is not the monotypic genus.…”